Modern manufacturing techniques usually rely on one or more production or packing lines, along which products are moved by means of conveyor belts, guiding rails or related transportation means. The actual manufacturing, production or packing stages usually require some kind of information on objects (e.g. a product) being subject to the respective manufacturing, packaging, inspection or release action.
From the conventional arts, there are known numerous devices and methods for determining a position or orientation of objects on the lines, the type or class of a present object, the presence or absence of objects, counting the number of objects passing a given point along the line, and the like. Common production stages include working on the product for applying or modifying product components, and common packaging stages include wrapping a product, applying product labels, or applying identification marks, such as clear-text identifiers or one- or two-dimensional barcodes.
Also, object inspection may be involved between individual stages, or—for example—at the end of the line as part of quality control and product release. Such inspection may involve determining whether the objects are in a proper shape, e.g. whether the right labels were applied to the products, whether the individual products show indications toward a damaged or incomplete product, and the like. Also for auditing and controlling purposes, inspection may involve gathering information on how many objects of some type (or class) are passing certain points in the line. The latter may be of particular interest if the line processes more than one object class, e.g. different types of products.
The above-mentioned auditing and controlling aspects may be of particular interest when taxable goods are considered. Specific examples for such taxable goods include alcoholic and non-alcoholic drinks (beer, wine, liquor, soft-drinks, etc.) and tobacco products (cigarettes, cigars, loose tobacco, etc.). Fraud in the imports, manufacture and distribution of such goods can cause substantial loss in government revenues. For example, a manufacturer of soft drinks could deliberately mis-declare the true type of a product (i.e. tax class) so that tax liability is reduced. Existing tax collection systems rely on voluntary tax declarations by the manufacturer, which may be difficult to verify.
In the context of the present techniques, examples for objects and products can, however, also include consumer products in general, electronic, electric and non-electric devices, food goods, beverage packs, cans and bottles, cigarette packages and other tobacco products, documents, certificates, money bills and the like. For example, a packaging line fills beverage bottles of different types, so that bottles of different brands and taste move along the same belt or rail.
Conventional devices and systems for obtaining object information along production and packaging lines involve code scanning, such as barcode reading, radio frequency identification (RF-ID) tag reading, mark sensing, laser scanning, light barriers, image processing, and the like. These techniques have different impact onto the general line setup in terms of requirements on the objects (e.g. necessity for barcodes or RF-ID tags), requirements on and modifications to the line equipment (e.g. installation of light sources and sensors, and the like), and requirements on the sensor equipment as such (e.g. power and processing resources).
Further, most of modern production or packing lines are optimized for high product throughput and efficiency. For the former, it is needless to say that line speed, i.e. the speed that the products move along the line or with the belt, and product density, i.e. the spatial and timely distance between two consecutive products appearing at a given position, are certainly important figures in the field of manufacturing and packing. Therefore, it needs to be considered that objects may pass by fast, that the density is high, and that even more than one product/object passes by at the same time.
The large number of such requirements, restrictions, and prerogatives leads to still unsatisfactory performance of conventional object classification in modern manufacturing, production or packing lines. Therefore, there is a need for improved object classification that is reliable, fast and less intrusive to the existing line setup and equipment. Further, in the specific context of taxable goods, an efficient and tamperproof means is needed to verify the correspondence between the declared tax and an actual output of products of a certain class.